New rider; boyfriend wants me to join him so we can have a hobby together

Basically what the title is but I’m asking for any advice on riding; I know the basics but I’m also scared of hurting or injuring myself on the bike and quad,but going on walls, in the water runoff trenches(do you know what I mean?) mud and sand+ ETC. I want to join him bc I know that’s his stress relief and I want to have a bonding activity that he enjoys too. Yes I have a helmet and riding boots…