Follow service manual remove old ram, install new ram.

ram spec

Optiplex 3050 Spec Sheet 

So you didn't list your current configuration.  If you have 4GB and Win10, your PC's speed will definitely improve with 8GB RAM.  Beyond 8GB is good for RAM heavy apps or servers.

KVR (Kingston Value Ram) isn't recommended for Dell's.  Not that it never works, but we've seen problems in this forum.

Crucial RAM comes highly recommended.  Guaranteed to work in Dell's and has a lifetime warranty.  https://www.crucial.com/compatible-upgrade-for/dell/optiplex-3050-tower 

I use A-Tech RAM, which is a little less costly than Crucial and also has a lifetime warranty.

SSD also increases speed and overall responsiveness.

Optiplex 3050 RAM list on Amazon 

It's not said what form factor/size your 3050 is.  Micro takes different RAM as compared to MT & SFF.  UDIMM for MT & SFF and SODIMM for micro.

i need dell optiplex 3050 16 GB Ram