You can show or hide columns from the View menu of the Gantter editor.

There is a "baseline columns" options under the "Baselines" menu of the Gantter editor. You can hide the "Baseline Cost" column from there.

The following are the steps to rename a "Custom Column" in your project:

1. Open up the Project Properties dialog by choosing the "Properties" option from the "Project" menu in the Gantter editor.

2. Go to the "Columns" tab of the Project Properties dialog.

3. Type in the names for the columns here

4. Click the "Save" button

You can do that by modifying the resource's calendar.

Double-click on a resource from the Resources tab to open the Resource Properties. You can then go to the "Working Time" tab to update calendar details.