The first step for me would be to identify the region upstream of the transcription start site that is most likely to contain the transcription factor binding sites (= core promoter region). For this, I would get some open-chromatin data (e.g. ATAC-seq from ENCODE or scan GEO/NCBI for datasets) from a closely related cell type and then determine the peak summits for the signal right upstream of the TSS. This should give you a proxy of the region to scan. Once you have the target regions, I would probably use FIMO from the meme suite against the JASPAR2018 core vertebrate collection of transcription factor motifs to identify significant transcription factor motifs. This would be an approach driven by motif occurrence.
Alternatively, you can intersect your promoter regions with the ReMap database, a collection of ChIP-seq derived transcription factor binding sites in human. This would probably be more biologically-correct as motif occurrence alone does not necessarily imply TF binding and some factors may have degenerated or non-canonical motifs that are difficult to detect. You can also try a combination of both approaches of course.
Also make sure to use google and the search function to scan previous threads for ideas:
Determine Transcription Factors For Genes
find transcription factors in a list of genes
Finding transcription factors binding to promoter of a gene or operon in bacteria
Identify Transcription factor from a list of genes