I need a diagram of how to change out 2 screw in fuse box to a homeline load center with 2 breakers it has 1 hot and 3 others cold please help

Please consider contacting several licensed electricians and get bids for this work.

If this is your main service panel, you have to pull the meter so that the panel will be dead. Utility companies normally will not allow unlicensed people to pull meters.

If this is a secondary panelboard, then the feed to this panelboard must be shut down.

There is no diagram that can be drawn based on the scant information you have provided. However, the electrical requirements and a layout of the panelboard will be provided within the panelboard's packaging.

There are no diagrams or instructions for a job like this. It is assumed you know what you're doing when you purchase this sort of equipment.
If you need such detailed instructions you should not be doing the job.
Contact a few electricians and get prices. It's as simple as that.

Even if you can do the physical work, the hard part is knowing what to do and why. A job like this cannot be described in a diagram.