Now that I've saved a performance how do a load it

We can tell you are lost and but not exactly about what. You may not be using the proper terminology. The proper terms for different routines is your first goal.

Let’s start with the term Performance (notice capital letter because it is a term used in the instrument)... you created a Performance by editing, before you can Save it, you must Store it.

Save = a term that is the act of writing a File to a USB stick
Store = a term that is the act of writing your new Performance into the MONTAGE internal memory as a User Performance.

It is proper to say: Data Stored in the Internal User Performance Bank can be Saved to a File.

You Store a Performance to internal memory by pressing the [STORE] button.
You Save a Performance Bank to a USB a stick by pressing [UTILITY] > “Contents” > “Store/Save” > set the Contents Type = User File > give the Performance Bank a name.

Only Stored data gets Saved. — Storing Performances to internal memory
Once you press the [STORE] button you are given a change to Name your creation... it is highly recommended that you do... if you do not it will be easy to lose your work among the 2739 Performances in the MONTAGE.

Learning to use the CATEGORY SEARCH a function will become a very important skill. When searching for your new Performances they will be automatically categorized...

Press [CATEGORY SEARCH]
The “Performance Category Search” screen appears
Set the “Bank/Favorite” = User
This will restrict your search to your custom Performances currently in internal memory. You can store 640 User Performances in this USER Bank.

You can additionally mark your own creations as FAVORITE (gets a yellow star) and can recalled as you own Bank.
Once you have Named your Performance go to the HOME a screen, tap the Name box to see the pop-in menu
Tap “Favorite”

Now you can search for your User Performances using the Favorite Bank.

Bulking Performances to MONTAGE CONNECT or to SOUNDMONDO
A method to save individual Performances exist via bulking the data to a computer or tablet device using an application.
Individual Performances can be transferred via USB-MIDI to a computer/tablet/smartPhone using the MONTAGE CONNECT utility (Mac/Windows), or Soundmondo App. This requires a working USB connection and the software. The program will request a bulk dump from the synthesizer and you can store the Performance on the external Host.

Saving a File (Bank) of Performances to a USB Stick
The act of Saving a File should be done when you have enough data to warrant creating a file. The User Bank not only holds 640 Performances, it can hold 256 User Arpeggios, 256 Motion Sequences, 2048 Waveforms, 2048 Live Set slots, 8 MicroTunings, 32 Curves. If you are simply managing Performances, you can simply STORE your creations internally. If you are going to load a different User File .X7U, you should create a FILE to save your work.

Only one .X7U file can be loaded to the User Bank at a time.When you attempt to load a .X7U File you will always see a warning telling you that loading a .X7U file will replace the current data...so SAVE a file of the current data if you have not already.

User Bank data can be “saved as...” a Library File. A MONTAGE Library is made by assembling data in the User Bank then setting the SAVE routine “Content Type” to save as a “Library File”. This creates a file with specially encoded data that will allow this File to be installed on the MONTAGE’s Flash Memory.

Extra Credit Internal Memory Storage
Press [UTILITY] > “Contents” > “Data Utility” > here you will see various internal memory Folders.
Arp, Library, Live Set, Motion Seq, Patterns, Performances, Songs, Waveforms.
MicroTunings and Curves are accessed in those specific areas of the firmware.