Succot lasts seven days. But only the first day is a Yomtov (or the first two days in the diaspora) and carries the prohibition against doing any labour, with the exception of cooking and carrying. The subsequent five or six days are Chol Hamo’ed —the everyday days of the festival.
Chol Hamo’ed has its own status, neither Yomtov nor a regular weekday. One should not do work on Chol Hamo’ed whose purpose relates to after the festival. If you needed to tidy your garden for a Succot party, that would be fine. But using Chol Hamo’ed to finally tackle the garden you’ve put off dealing with for ages could be problematic.
Challengingly, going to work is only really allowed in cases of davar ha’aved, when something would be lost by not doing so. If by staying at home, you would not merely suffer lost income but actually be out of pocket, you may work. It is possible to keep this halachah when in Israel, where many businesses and government offices are closed throughout the whole of Succot. In the diaspora, where taking Yomtov off is hard enough, not working on Chol Hamo’ed is well-nigh impossible.