Hi @Buggydav ,
Do you want to edit your Portal Page within your Portal Designer directly?
If you want to add some images, change text or add Text, I think you could achieve your needs in Portal Designer directly. Currently, supported components within the Portal Designer could help you add some images, changes text or add Text:

If you want to move some things around on the Portal, I afraid that there is no way to achieve your needs in Portal Designer directly.
In addition, for some other things, e.g. configure Web Forms, Authentication way, ..., these settings you could not achieve in Portal Designer directly. You need to go to your Portal Management, configure these settings there.
Generally, all things you want to configure in Portal Designer directly could also be configured in Portal Management. You should go to Portal Management to configure settings for your Portal, which is better than that in your Portal Designer directly.
Regards,