Change domain of my blog in Blogger

I have a blog with 95 entries and 30 pages. The blog is in Blogger and my domain is with 1and1.com. FIRST STAGE TASK: I want to change the domain so I will buy another domain first. The task is to change one domain for the new one, but not loosing SEO. The subtasks are: - Connect the domain to the blog (DNS and so on) - Redirection 301 of the whole blog (or maybe you think it is better for SEO page by page (I have around 100)). - Install the SSL certificate (in theory I have it installed with blogger, but ir does not work in all pages) - Upload the [login to view URL] to Google Search Console - Connect new domain to Google Analytics - Any other task you propose is wellcome (apart from link building or other SEO long-term strategies). I know all tasks are less than 5 minutes each, but I want someone who is used to do them so that I don't loose SEO and everything is correctly done. SECOND STAGE TASKS I have other taks to be done as well, but for a later stage, such as: - redesign (HTML+Css) of this page [login to view URL] - make a Google Script App. This script should do the following: when a user pays me through Paypal, the script capture his email address, name and amount paid, writei it down in a Google Spread Sheet which is in my Google Drive, copies a password from that Google Spread Sheet, and send the client an automatic email telling him what is his password. - a formula in Google Spread Sheet that, given this web address [login to view URL] (or any other company instead of Disney), gets the price of the shares of Disney, and writes it down in the sheet (note: with importdata or importhtml I was not able, it is somehow protected). - migrate my blog from Blogger to Wordpress. Please, provide: - your quotation for the first stage task (domain change), - do you propose any other subtask (apart from DNS, 301, SSL, sitemap, analytics)? - do you have experience changing domain for blogger? - your quotation for each of the second stage subtasks quotation. If you don't want or cannot do the second stage task, it doesn't matter, please proposal just fot the first stage. Thank you very much. Ignacio