Sign up at app.ascensie.com/auth/sign-up. There is no waiting list and no invitation code.
On the sign-up screen, enter your email address and a password of at least eight characters. If you would rather not have another password, use Sign in with Google instead.
If you sign up with a password, you will get a confirmation email. Follow the link in it and you are in. Check your spam folder if it does not arrive.
Lost your password later on? Use the "Forgot your password?" link to have a reset link sent to you.
After signing in you land on your personal account. It holds your home page and your profile, and not much else. That is deliberate: your personal account is your login, not your workplace.
Under Profile you set your name and your picture, and you can turn on two-factor authentication with an authenticator app. Worth doing, especially once customer data goes into the CRM.
The real work happens in a workspace, also called a team. Your contacts, your mail, your quotes and your invoices all live there. A workspace has members with roles, and those members share everything in it.
Create one from the workspace switcher in the top left: New team. Give it a name and confirm. If you have no workspace at all yet, you get a screen inviting you to create your first team instead.
The name also decides the address of your workspace. If your name contains characters that cannot go in a web address, the form asks you to pick a team URL yourself: letters, digits and hyphens only.
Once the workspace exists, the full sidebar appears. What is in it depends on which modules are switched on.
If you belong to more than one workspace, because a colleague invited you for instance, use the same switcher in the top left. It lists all of them, your personal account included.