Download the font file from a trusted source
Unzip the font file if it is compressed
Locate the font file in .ttf, .otf, or .ttc format
Install the font on your computer
Windows: right-click the font file and select Install or Install for all users
Mac: double-click the font file and click Install Font in Font Book
Restart Photoshop if it is already open
Open Photoshop and select the Type Tool
Find the installed font in the font list
Use the font in your design