Forumites will ask you for a lot more information than just 10x16:
First, on you own, sketch out a early rough plan using the allowable space dimensions [10x16?]. You can do it to 1/2" =1'-0" scale on a 11"x17" cheap sketch pad with pencil and ruler [if good with a computer there are software programs]. This step provides some dimensional preciseness which becomes important as you began laying the track and placing structures.
For working on the layout you need to be able to reach all areas of it from the edge[s]. So, around-the-wall type with open center walkway space and about 36" maxium wide benchwork each side/end [depends on your "reach"] is one good method in an closed loop with "duckunder or lift section for access. If an "Island" type is used to enable a "dogbone" or return loops at each end, you may need to have access holes out in the layout to enable servicing it.
You need to decide on a track plan with mainline[s], sidings,spur tracks [a Yard?] and in doing so try to keep the track back from the edges or wall by about 6" for clearance of longer equipment.
In your planning avoid covering the layout with too much track--leave ample room for the type of structures and scenery you prefer. Just ask on particular items, events or materials. You will receive much advice from here on the Forum regarding basic layout planning, bench work materials, type of track available and so forth.
You can go to the "Layout" section of the Forum and view many layouts under construction including relative easy 2x4 post and beam with 1x4 upright grid joists and plywood top cover, Linn Wescotts [book available] "L-Girder System" which is lighter construction [I used it in HO days--basically 2x2s/1x3s] but requires much more fabrication than basic 2x4 post & beam construction with standard size off the rack 2x4 & 1x4 lumber components.
Use screw/bolts to assemble benchwork components---nails are too permanent and a "wreck" upon removal if necessary.
Just a few thoughts--good luck. As an example close to your dimensions, the photo below shows what 9' x 16' in a 9x19 attic room looks like--w/ hinged Drop Section access.