How do you install a custom rom

[nemuhiro]

Hi guys, just want to ask how to install custom roms sa mga adroid device.
I have this phone and its kinda laggy, does installing a custom rom minimizes the ram usage

 

[xGENOCIDE]

Via ADB anong device mo ba at anong gusto mong custom rom na ilagay nakakatulong din naman amg custom rom para mawala mga bloatware

 

[Iridescencez]

Sa pc or via custom recovery kung phone lang meron pero need rooted