What is the general formula of the alkanes?
The root word -ane tells you that it does not have double bonds.
Alkanes are chains of only carbon and hydrogen, connected only by SINGLE BONDS.
There can either be straight chain or branched alkanes.
However, the rule of thumb is to find the longest carbon chain and name them accordingly.
Simply add -ane to the prefix and if it has any branches, add -yl to the end and name the branches with numbers.
It's perhaps necessary to memorize the list shown here for your convenience - and lots of practice as well.