To properly install a custom simulation analysis or instrument in Multisim (created using LabVIEW), follow the below steps:
1. Open Multisim and check the default location for the User LabVIEW instruments path under Options»Global Preferences as shown below
By default, this path should be: C:\Users\Public\Documents\National Instruments\Circuit Design Suite 12.0\LVInstruments
2. Download the LabVIEW .LLB and .DLL files of the analyses (check the documents section of this community) and save them under the folder specified in Multisim Global Preferences as shown below
3. Restart Multisim, and these tools should appear in the Instruments toolbar under LabVIEW Instruments as illustrated below