I'm afraid you picked out a very difficult model for your level of knowledge.
To make a parametric model of a grub it's a challenge also for some experienced CAD user.
1'st Possibility: search a little bit in internet about free cad models of grubs in STL format and use them.
2'nd Possibility: you have to learn how to master your cad tool.
your right its a mined feild out with the cad tryed down loading free cad with no look .so would you been intrested in doing some work for me like i say i would pay you .how much do you think it would cost for the work i require ,regards david
thanks 4 the pics u sent me but i need solid 3d cad i can,t use thse one to pirnt the parts i need iam just going round round can,t fined wot i want can u help please regards david