The game starts in the marsh, where you can help members of Clear sky out and visit there base where you will have the opportunity to use the base facilities, Do tasks such as finding tools for there tech so you can get upgrades done there. There's no need to rush off take your time and prepare for what is to come.
You have a lot of free time on your hands, I cant even seem to find the time to finish SGM 2.1 but you are already into other mods...