Mistakes
They must to come
We have decided to come in office
Only 1 people each times
The official day to reopen about the company is 4th May
This week is the first time to come in office for me
If there will be a good weather
If you consider the normally situation
Solutions
They must to come
They need to come
We have decided to come to the in office
Only 1 people person each times
The official day to reopen about the company is 4th May or The official day of reopening
After a preposition use a verbing
This week is the first time (that) I to have come in to the office for me
Here is another example: “this week is the first time I have been for a walk to the mountains since February”
If there will be a good weather or if the weather will be good
‘Weather’ is an uncountable noun.
If you consider the normally situation