# Calculate confidence interval for hazard ratio given maximum likelihood and standard error

I'm doing a meta-analysis and one of the studies presents the hazard ratio (HR) with the maximum likelihood estimate (MLE) with its standard error (SE). The rest of the studies give the HR and the confidence interval (CI) for the HR. Now, I know how to the the SE for the HR given the HR's CI. My question here is how can I get the HR's CI from the first study given only the MLE and its SE (the standard error of the MLE). This is my first meta-analysis and my first jump into this type of statistics so my question might be very bald for most of you.

I was looking here: http://www.mas.ncl.ac.uk/~nmf16/teaching/mas3311/week10.pdf but in the example they put they calculate the HR's CI for data when there is no more differences between two individuals. I guess the results from a survival analysis can't be interpreted that simple so I can't applied the same maths... Or maybe I'm just struggling with the interpretation of these concepts in general.

If anyone could give an example of how to do it correctly or give me a link to look at to understand better, I'd really appreciate it.

Thanks!