Site stub?

Question

Google

Started building a new brand. The brand has retail outlets and a website that is under development.
There is a distribution of advertising materials to attract traffic to retail outlets, but the address of the future site is placed on the advertising layouts, so people come in, but there is no one there.
1. Is it worth hanging a stub with information that the site is under development or the like?
2. If so, how should it be presented in terms of content and what elements should be placed (forms for e-mail, etc.)?
3. Is it worth opening a page for indexing by search engines?
4. If so, is it necessary to place keywords on the page? By the way, the keys have not been compiled yet, but is it possible, for example, to use any basic theme keys, such as "Premium Furniture"?

Answer 1

1/ Yes, a stub is needed, let it settle on the domain.
2/ Preferably contacts. Form - optional
3/ Open for robots is worth it + set the counters and register with the webmaster to see what requests are being clicked.
4/ Keys put in h1 and meta tags title and descr - minimal