Step 1 Upload the SPFx package

a) Log in to www.office.com and click the App Launcher Icon on the top left corner of the portal.

b) In the flyout menu select admin

c) Click on "Show all"

d) Under Admin centers, select SharePoint

e) Click More features

f) In the Apps block, click Open

g) If the App Catalog was previously created you’ll see the below:

h) Otherwise, a new App Catalog will be automatically created

i) When the provisioning process is completed, you’ll see the confirmation message below. Click on Got it

j) In the Manage Apps page, click on Upload:

k) Navigate to the location where you’ve stored the solution file

l) On the next screen, select the option to only enable this app to make it available for site owners to add from the My Apps page:

m) Once added, you’ll receive the below confirmation message: