I can only tell you that the grammar rules for Twi are different from the grammar rules for English, so don't expect success in translating a sentence simply by translating each word.
twi.bb does not have a grammar section (and probably will not have one anytime soon) but you can learn a lot by using the search feature of the dictionary to study how words are used in Twi sentences. For example, you could search for words/phrases such as "laugh", "eating", "sleeping", "eaten", "I am", "He is", "We are", etc. and compare the structure of the sentences in the search results.
And here's a tip... when searching for sentences which contain "eaten", add a space before it like this " eaten" so that you don't get sentences containing "beaten".
My experience with the "official" dictionaries is that there is bound to be conflict between them because Twi is mainly a spoken language as opposed to a written one. Best option is to find someone who can speak the language fluently... failing that (or in addition to that) get as many "official" dictionaries as possible, compare the entries to see where they agree and where they differ. Take your time to master it gradually and don't be in too much of a rush because there is a lot to learn.
Kwame the Webmaster.