Ho replaces a whole idea rather than a specific noun: ho arreglarem, no ho sé. En replaces a phrase with de, which is why encarregar-se de becomes me n'encarrego. Both go before the verb, or hook onto an infinitive.
Examples
- No t'amoïnis, ja me n'encarrego.
- Do not worry, I will take care of it.
- Ho arreglarem aquesta tarda.
- We will fix it this afternoon.
- No ho sé, però ho preguntaré.
- I do not know, but I will ask.
The mistake to avoid
Use ho for an idea and el or la for a specific thing you have named.
Where this fits in
Telèfon, missatges i petits problemes, Catalan A2: Trucar i escriure, demanar disculpes, aclarir un malentès i demanar ajuda - el dia a dia quan alguna cosa no va com estava previst.