How would I go about reading and separating this text file's information into arrays?

This answer is maybe not complete but it will help you, at least, with the processing of the lines in the text file.

Assuming a file.txt as the input file, and with the following format

Adam: Tall Handsome Kind Athlete
  He enjoys playing basketball

Sabrina: Short Pretty Funny Adorable Gymnast
  She loves gymnastics

Sinclair: Blonde
  He is blonde

We can process this file as follows

#include <string.h>
#include <stdio.h>
#include <stdlib.h>


/*process_info_line: process the line with the name and attributes*/
int process_info_line(char *line)
{
    char *next = NULL;
    char *part = strtok_r(line, ":", &next);
    if (part)
        printf("NAME: %s\n", part);
    else
        return 0;

    while (part != NULL) {
        part = strtok_r(NULL, " ", &next);
        if (part)
            printf("ATTRIBUTE: %s\n", part);
    }

    return 0;
}

/*process_sentence: process the line with the sentence*/
char *process_sentence(char *line)
{
    line = line + 4;
    return line;
}

/*is_sentence: checks if the line is a sentence, given your definition
 * with a tab(or 4 spaces) at the begining*/
int is_sentence(char *line)
{
    if (strlen(line) == 0)
        return 0;

    char *ptr = line;
    int space_count = 0;

    while (ptr != NULL) {
        if (strncasecmp(ptr, " ", 1) != 0) {
            break;
        }
        space_count++;
        ptr++;
    }

    if (space_count == 4)
        return 1;

    return 0;
}

/*scan_file: read each of the lines of the file and use
 * the previous functions to process it.*/
int scan_file(char *filename)
{
    char *line_buf = NULL;
    size_t line_buf_size = 0;
    ssize_t line_size;
    int line_count = 0;

    FILE *fp = fopen(filename, "r");
    if (!fp) {
        fprintf(stderr, "Error opening file '%s'\n", filename);
        return 1;
    } 
    /*Get the first line of the file*/
    line_size = getline(&line_buf, &line_buf_size, fp);
    while (line_size >= 0)
    {
        line_count++;
        line_buf[line_size-1] = '\0'; /*removing '\n' */
        if (is_sentence(line_buf)) {
            printf("SENTENCE: %s\n", process_sentence(line_buf));
        } else {
            process_info_line(line_buf);
        }
        
        line_size = getline(&line_buf, &line_buf_size,fp);
    }

    // don't forget to free the line_buf used by getline
    free(line_buf);
    line_buf = NULL;
    fclose(fp);

    return 0;
}


int main(void)
{
    scan_file("file.txt");
    return 0;
}

This will generate the following output

NAME: Adam
ATTRIBUTE: Tall
ATTRIBUTE: Handsome
ATTRIBUTE: Kind
ATTRIBUTE: Athlete
SENTENCE: He enjoys playing basketball
NAME: Sabrina
ATTRIBUTE: Short
ATTRIBUTE: Pretty
ATTRIBUTE: Funny
ATTRIBUTE: Adorable
ATTRIBUTE: Gymnast
SENTENCE: She loves gymnastics
NAME: Sinclair
ATTRIBUTE: Blonde
SENTENCE: He is blonde