How about a few tips to get you started...
Start with a wheel. Create a new part. Think of the cross section, looking across (not along) the axle. Sketch the top half of this. make it a closed loop. Draw a line representing the axle. Fully dimension everything, so that the line on your status bar says "Fully Constrained" or similar, but don't necessaryliy get too hung up on this. Exit the sketch, and revolve the loop around the axle line. Viola! Wheel complete. Save.
The Deck: At your level, flat will probably be sufficient. start a new part (ipt). On the first sketch, draw the plan view of the deck. fully dimension it, and try to make it symmetrical. Tip: draw a rectangle, and dimension that to get the scale right. Then put some arcs in to round off the corners suitably. Trim. Exit sketch, and extrude 10mm or whatever. Save. Rightclick on the part name in the browser, choose iProps, and change material to Wood- whatever. Save. Do a sketch on the bottom side. Hold F4 and drag with the mouse to change view, or drag the view cube (in the top right corner), or click on the view-cube. Put in 4 points for the truck mounting holes, in two places. Dimension them. Exit sketch. Create a hole feature, change dimensions of the hole to suit. Save.
Repeat for bearings (Revolve, like the wheel), don't bother modelling the balls, just the inner diameter, outer diameter and width.
Repeat repeat for the Axle (with another revolve part).
Trucks: New Part. Start with a big ol' rectangle. Extrude solid. Now do some sketches and Extrude-remove to get rid of everything that doesn't look like the trucks. Save. (Yeah, i know, this was a bit of useless modelling advice, but the trucks can be as simple or complicated as you want.)
Now to put it together.
Start a new Assembly file. Place the deck. It will automatically be grounded; this means it can't move. Now place the truck part twice. You should have put some holes in them to match the deck holes. Click constraint, and change to insert type (The one on the right, 4th one across). select a hole on the truck, then a hole on the underneath of the deck. The truck should move. Repeat with another hole to align the truck. Save. Two insert constraints has now fully fixed that truck. You won't be able to drag it any more, whereas the other truck will still be "loose", and you should be able to drag it. Note, if you click the wrong holes, or if your hole centres are different, then you will get an error. You can expand the part in the browser to edit the constraint, etc. Maybe use an angle constraint instead of the second insert to fix things up if you're have proplems. Save.
Repeat with the second truck, so it is fixed in place. Save.
Repeat with axles, (Save.) bearings (Save.) and wheels. Save.
Cool, now you're almost done, but you can't really print that out. Start a new file, a drawing (idw). place new base, and make sure you choose the assembly. Ensure the orientation is correct. Place some projected views. Right click, and continue. Save. put some dimensions on. Save. If you want, do some section views, and dimension these. Save.
Ensure that the title block is filled our with your details. Save. Close all files, and create a zip file containing ALL files you have just created: all ipt (part) files, the iam (assembly) and the idw.
Email this file to your teacher, or submit it however.
Come back here, and thank me.
Then try to model something else from your life. Use search here to find out how to solve problems you come up against. try to help other people. Go to college and get a degree (or diploma or something) and get a job designing funky, unique and interesting stuff, that no one else would ever have thought of.
And in 15 years time, think of me, and this post, and laugh.
(I wonder if my FEA simulation is done yet...)
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This is my signature, not part of my post.
. Can your guys help me to do this projects?. I very very appreciate ur guys. i have to turn in this friday 
