Quote: "I would love to ask were I should get started with leaning basic code."
There is a whole other board for newcomers with suitable sticky threads at the top of the page here
https://forum.thegamecreators.com/board/7
Quote: "I would also like to know what other plugins there are"
Paid plugins
http://www.thegamecreators.com/?m=view_product&id=2000&page=packs
Free plugins
https://forum.thegamecreators.com/thread/38709
This is probably not an up to date full list but this board is the dll board which is how plugins are implemented, your best bet would be to check both lists to see whats available, if you want something not there you can always make a thread to ask specifically if anyone knows of one suitable for what you need...you may find some links don't work or product is no longer available. You may even find compatability issues with various dark basic pro update versions, been a while since I tried many of them. One link that is not in that free list that is a must have is this
https://forum.thegamecreators.com/thread/85209 and one that is no longer available but not on the dll board is instead in the program announcements board here
https://forum.thegamecreators.com/thread/154086
Quote: "what other things I should consider before moving on with my project"
There are many many many things, just make a start for now using tutorials, as you progress you will start to realise more about lots of different things. One thing you must be aware of is that your using the GameGuru version of DBP so some or maybe all those plugins won't work. You should install the free version of dark basic pro not from github but from here
http://www.thegamecreators.com/?m=view_product&id=2000&page=free. Then you may want to upgrade using any of the officially supported updates here
http://www.thegamecreators.com/?m=view_product&id=2000&page=upgrade7-62 or unofficially supported like for example at the top of this board(dark basic pro board) the last of the sticky threads the U77 public release candidate is available that has several versions of the upgrade. Of course you can still have any versions installed alongside each other by simply renaming their folder as I described in your other thread and just renaming the one you currently use to the correct name. ***Please be aware that you should install free version so you can see the correct folder name of the DBP install path so that what I wrote in your other thread makes more sense if you plan on using various plugins that don't work with GameGuru version - I had assumed you already had it installed before venturing into the GameGuru version***
You can use the forum search tool at the top of the page for anything specific or use google with "site:" followed by the url followed by what you want to search for with a space between them, eg "site: forum.thegamecreators.com newton physics", this is especially useful for specific boards as the old forums had a tool for that that the new forums don't. I haven't tested the new search tool fully but I am fairly certain the old search tool wouldn't provide more than a specific number of results(think it was 100) which was incredibly annoying, so searching on google this way is much better. Also lets say you happen to remember a post someone made in response to a certain thread and all you can recall is the name or names of the users along with the subject in question, searching on google this way again has come up trumps for me many times over.
If I was you I would work on getting familiar with every nook and cranny of this website such as the product page as well as the forums as this board isn't the only relevant one for DBP.
Quote: "is it possible to upgrade my game with things such as a newer version of directX"
In its current state its dx9 only. Its also limited to using 2Gb of ram.
Quote: " ...and create networking for the game so it can host some multiplayer capabilities"
Yes there are commands(I think they are listed in the gamefx section of the help file but in any case they are definitely there somewhere, they aren't as good though as some free plugins or the one that you can purchase(called darknet)
Quote: "Is it also possible to upgrade the coding or use darkbasic along with other languages such as C++ and JS in the same game? "
Not JS but pretty sure they released the source code on something called svn tortoise or something to that effect, what variant of C I don't know offhand and I don't have time to search I'm afraid, besides which its a first for me to look at anyway and I don't know any other language other than DBP. The GameGuru version your using currently came with source code and its significantly different to that of the old version I gather. You also can write your own plugins in some variant of C I gather but all of this depends on your own skills/coding experience you have.
Anyway have fun, its quite verbose(in terms of what I have written) but all in all your not going to be stuck with nothing to do lol, best of luck