I'd definitely be interested in adding a tutorial in the future but currently because I'm changing so many things relatively often it wouldn't be worth the time to make a tutorial for things that may end up changing in the next update. I can always update the tutorial as things change, it would just take more time. There are some things that will always stay relatively similar so I could look into doing a quick "basics" tutorial that would introduce new players to the game. Ideally I'd have this in the game itself so I'll note it down as a wish list item for one of the next couple of updates.
For the jobs: jobs themselves aren't assigned, you just create the job by placing down something to build or directing them to cut down trees, mine stone, etc. and they will automatically take and complete the jobs. This is done by selecting the job from the bottom-left menus and then clicking or clicking and dragging over the area that you'd like the job to be performed.
I may investigate adding the ability to specifically assign a colonist to do a job if it would be very beneficial for them to do that one, however I've been slowly trying to improve the job distribution algorithm to the point where a colonist would nearly always take the job that is best for them however this is not the case currently.
You can assign colonists professions which will make them prioritize jobs within that profession (e.g. a Miner will heavily prioritize mining jobs) and that is done by clicking on Professions on the top, clicking the + on the profession you want to add the colonist(s) to, and then clicking on the button that appears for that colonist.
I have plans to make more general professions that cover more jobs under their umbrella (so you'd have Labourer, Farmer, etc. instead of separate professions for Mining, Digging, etc.).
There's definitely still a lot of work to be done on the game and especially the job distribution algorithm (as my own playtesting very often has colonists not doing what I'd like them to be doing) and I'm slowly working on the game when I have the time.
Thanks for checking out the game! Sorry for the wall of text haha