Only ACTIVE materials will appear as available in a design. This helps ensure that the drop down list of materials when you make a change in a design only includes materials that you would use. 

In the Inventory module go to the material and confirm the following:

For ALL materials: Make sure ACTIVE is checked at the bottom of the screen for the material you want available

For  Lumber:  If the material will be used as a CLEAT component and you are replacing the default material for another in your active inventory then ensure the CLEAT checkbox is selected. This option allows you to no show materials that will not be used as cleating not appear when that component is changed. 

For Fasteners: Ensure the correct boxes are checked for how the fastener will be used. Select as many options as applies.

 By default your fasteners will not appear on the cut sheets. You may opt to have fastener information print out by un-checking the 'Exclude from Cut Sheet' box

If the material isn't in your Inventory active list then click on the Inactive tab and check if its there before adding a new item. If so mark it as active and update any of the information for your shop. Items already in the Inventory have some pre-entered information which can be helpful such as correct weights and install times. 

If its not there in your Inventory you can add it (and any material) by being in the tab you are adding it to and clicking on New at the top of the screen.