how do you do ratios

Ratios are like fractions and you could convert them.
Ratios use colons like this:
E.g. 5 : 2
Have you looked at the videos before?
https://www.khanacademy.org/math/pre-algebra/rates-and-ratios/ratios_and_proportions/v/introduction-to-ratios-new-hd-version

A ratio is simply a fraction like 1/2.... You can say it has a ratio of ONE to TWO..... If you multiply the numerator (top number) and the denominator (bottom number) by the same value you will end up at an equivalent ratio..... let's say we multiply both by 2.... we get 2/4... which is still a ratio of ONE to TWO.... an equivalent ratio.... as long as you multiply OR divide both the numerator AND the denominator by the same quantity, you will end up at an equivalent ratio every time

There are a LOT of things in mathematics going forward that rely on manipulating ratios, so get familiar with them early on.... I suggest mastering everything on Khan Academy starting with even the early math.... It will build you a great foundation by making things like ratios clear to you

I hope this helped!
Jeremi