1) To install custom gloves in Counter-Strike: 1.6/CZ, you need HLMV (Half Life Model Viewer) which can be downloaded here.
2) Next, open HLMV and click "File" click "open" then click "Load Model" and load the model you want to put the custom gloves on.
NOTE Make sure it's a "V" model and NOT a "W" model or a "P" model.
3) Once the model's open, click the "Textures" tab in the HLMV menu, which is at the bottom of the window. Then click the long box that's right underneath the "Model Display" & "Body Parts" tab and find the glove texture and select it.
NOTE You can't replace CZ mesh with Source mesh or vise-versa.
4) Next, click the "Import Texture" button in the bottom right corner of the window, and find the glove texture that you want to "Import" or "Install" and select it. Now you should have your new gloves installed!
NOTE You can only install glove textures that are the same size as the gloves your replacing.
5) Finally, click the "File" tab again and scroll down to "Save Model As". Now find the model that you put the gloves on. For example: v_deagle or v_ak47 and save it in your models folder. Finally, your done!