Go to the BP_ControlsSettings widget then also open the BP_ServerBrowser widget and copy the videos below.

Next create a new function called ResetDefaultAxis then copy then copy the image below.

Next create a new function called ResetDefaultAction then copy then copy the image below.

Next in the event graph copy the image below.

Next select the DefaultAxis variable and in the details set the Defaults Values shown in the image below. To add new entrys to the defaults values click the + button. The Key (Name) variables must be identical to the image below.

Next select the DefaultAction variable and in the details set the Defaults Values shown in the image below. To add new entrys to the defaults values click the + button. The Key (Name) variables must be identical to the image below. Note there are 2 images below for these default values!

I recommend opening the project settings then going to the Inputs section and copying each of the action name when adding these values to make sure they are identical to the images.

You have now finished, if you have added your own controls to the project you can add those here as well. If you want to assign a different key to any of the default values from the above image you can change that as well.