Hi,

1. How do you sum Time fields hh:mm:ss

You would only sum Time fields if at least one of them were a Time Duration field. You simply sum them and then FORMAT the result to suite your needs as you would any Date/Time value.
FAQ68-5827: Understanding Dates and Times & why they seem to be so much trouble?

2. How do I concatenate a text field and a date field

Since Date/Time values are numbers, you must convert your Date/Time value FORMAT using the TEXT() function as...

=TextFieldRef&TEXT(Date/TimeRef,"yyyy/mm/dd")



Skip,

_{Just traded in my OLD subtlety...
for a NUance!}
"The most incomprehensible thing about the universe is that it is comprehensible" A. Einstein

Power Query part of Power BI (actually the advanced editor code from excel), starting with tData query querying excel table, with two columns ('txt' and 'date'):

let
    Source = tData,
    FormatTextDateColumn = Table.TransformColumns(Source,{{"date", each Date.ToText(Date.From(_),"yyyyMMdd") , type text}}),
    #"Merged Columns" = Table.CombineColumns(FormatTextDateColumn,{"txt", "date"},Combiner.CombineTextByDelimiter(" ", QuoteStyle.None),"MergedColumn")
in
    #"Merged Columns" 

Most of the code are recorded steps.

combo