1. Navigate to the Pulse Instruments' Page by clicking on the name of the preset which is currently loaded.

2. Locate and click  the 'SCAN' button in the lower left corner of the Pulse Instruments List

SCAN button

3. Click the '---SCAN---.nka' at the top of the Pulse Instruments list. 

SCANdotNKA

SIGNAL will check the Data > Signal Presets folder for new presets. After the scan, your Pulse Instruments list will be up to date. For a full overview on how to download and install Expansion Packs for SIGNAL, check out this video tutorial.