Boats need the skill 'Wheelmaking'. Look up the skill tree to find how to get to that. A house needs plowed earth and then that earth has to be paved with chips of stone. Seeds appear as little white flower thingys once you have foraging skill and your exploration is at 8 or more. Once you have the seed dry it on a drying frame (or more advanced herbalists table later on) then you can plant whatever random seeds comes from that windblown seed.
Or you can go raid/ask someone for seeds. I suggest you leave the seeds for later. Work on getting wheelmaking and build a boat and move to a new location. A border between grassland and forest would be nice for starters, but it depends on what you want.