how to use; usage instructions; directions for use
Refers to the method or instructions for using something, often found in manuals or on product labels.
Please read the directions for use of this medicine carefully.
If you don't know how to use it, please contact support.
使い方 is more casual and common in everyday speech, while 使用方法 is more formal and often used in written instructions or manuals.
Compound of 使用 (use) + 方法 (method).