There are a lot of them, in fact it's a pretty boring exercise, but it could be also quite interesting from some aspects...
Anyway, the structures you've written so far are ok, even if they are (almost all of them) written twice, flipping the molecule horizontally. This doesn't change the nature of the molecule or its geometry: here are your attemps matched together when they represent the same species.
The two structures written in red are the cis-trans isomers for hex-3-ane, you can find out the same isomers for both hex-1-ane and hex-2-ane, while the last two don't have this isomerism (try to understand why). There are still more structure to be found: my suggestion is to start from the double bond (writing the structure in the form of my E/Z hexanes) and add substituents, remembering not to skip any cis-trans isomerism. Moreover remember that a formula in the form Cn
can refer to an alkene but also to a cycloalkane