Ram upgrade for tensor book

I use windows 10 and in my performance log for memory it has 1 of 2 slots used. Does this mean I can buy a single 16 GB SDR4 ram chip and upgrade to 32?

If so what is the recommended purchase?

I am not from the LambdaLabs team, but a general recommendation is to buy the same chip from the same brand. Usually, you can mix brands but have to pay attention that the RAM sticks are the same speed and use the same voltage etc. If you get the same chip from the same brand, it minimizes the risk of unexpected issues.