Molecular Formula and Drawing Structural Isomers
For each molecular formula, there is the possibility for multiple structural isomers to be drawn. In the video below, I show that there are 4 possible structures that can be drawn from the specific molecular formula.
How to approach drawing structures
The first thing to do is calculate your degrees of unsaturation. This will tell you the number or rings and/or double bonds. You can see how to do this calculation in Guide to Solving NMR Questions.
Next, draw the longest chain you can. Use all your carbons. If you have any degrees of unsaturation, add them in.
Follow this up by adding the rest of your atoms. This is the best way get a starting structure.
Cis/Trans Isomers
In this video, we see that we are working with an alkene. I want you to notice the middle two structures. When looking at alkenes, make sure you always think about cis and trans.