Freelancers

I can set up a temporary office facility anywhere it is needed, during project management periods.

".... A freelancer receives payment for individual assignments without being a permanent or temporary employee of the organisation he or she is carrying out work for.
Freelancers (also known as "contractors") are half-way between an employee and a self-employed person, and have similarities with both.

Both freelancers and employees are regarded as salary recipients by the tax authorities and are not self-employed.
Both freelancers and self-employed persons carry out assignments outside of a employment relationship, i.e. you are your own boss. You carry out the work at your own expense and risk, and are not subject to an employer's instruction authority or ongoing checks on your work.

The differences between freelancers and self-employed persons lie in your rights and obligations. As a freelancer, you do not need to have an organisation number. You also have no responsibility to keep accounts, and you will not be liable to VAT. As a freelancer, you will receive a salary from your client, submit the tax return for employees and be entitled to the minimum standard deduction as a salary recipient.

Social security rights
As a freelancer, you have fewer social rights than employees. The client will not be liable to pay you sick-pay. You will not be entitled to holiday pay (unless you have reached an agreement about this).Freelancers are not entitled to occupational injury benefit or occupational injury insurance. Freelancers are not entitled to a pension scheme from their client...."

Source : Tax authorities / Altinn.no, Norway; last updated 2020.

https://www.altinn.no/en/start-and-run-business/planning-starting/before-start-up/freelancers/