Microsoft has built many of the standard Excel Add-ins such as Solver and the Analysis Toolpak into the program and do not need to be downloaded and installed, only turned on. I will provide instructions to do this below.
To turn on these add-ins, they ironically are not in the Add-In's menu. As both Windows and Mac have a different process, I will explain both below as I do not know what kind of computer you are using.
For Windows:
- Open Excel to a blank worksheet.
- In 'File' menu (upper left), click 'File', look to bottom item 'Options'.
- In 'Options' menu (new window), look for 'Add-Ins' in left hand menu.
- In Add-ins screen, select Analysis Toolpak and hit "OK" at bottom.
- In a small pop-up window, you will be able to select the add-ins you want to add, such as the Analysis Toolpak, VBA extension, and Solver Add-in.
- Add what you like and hit OK. These tools will then be available under 'Data' section in Excel.
For Mac:
- Open Excel to a blank worksheet.
- In Mac top menu, look for 'Tools".
- In 'Tools' menu, look for 'Excel Add-Ins' near the bottom of the menu.
- In the pop-up, select the needed addins such as the Analysis Toolpak and Solver Add-in.
- Add what you like and hit OK. These tools will then be available under 'Data' section in Excel.